Papers by Pavel Kosmachev
Letters on Materials
This work shows the possibility of obtaining hybrid layered metal-polymer composites based on low... more This work shows the possibility of obtaining hybrid layered metal-polymer composites based on low-carbon steel and aluminum alloys with interlayers of basalt fiber reinforced thermoplastic polymer-polyetheretherketone by methods of hot and cold bonding with the use of hot and cold curing adhesives, respectively. The adhesive tear and shear strength of composites obtained by two alternative methods and the impact strength of steel-polymer and aluminum alloy-polymer joints were evaluated. The tests of five-layered composites for impact bending on samples with "crack-arrester" type V-notch (with the orientation of the notch line across the composite layers) at temperatures of −60, +20, and +200°С were carried out. The analysis of the test results showed that the composites have increased strength at shear loads and resistance to brittle fracture at low climatic and high working temperatures. Fractographic analysis of the fracture surface of composites allowed to determine that the fracture proceeds through adhesive, cohesive, and mixed mechanisms. Cohesive fracture is initiated in the polymer layer by nucleation and crack growth along the fiber-matrix interface, as well as cracking of the basalt fibers.
PROCEEDINGS OF THE INTERNATIONAL CONFERENCE “PHYSICAL MESOMECHANICS. MATERIALS WITH MULTILEVEL HIERARCHICAL STRUCTURE AND INTELLIGENT MANUFACTURING TECHNOLOGY”
The mechanical characteristics of PEEK-based layered composites with unidirectional carbon fibers... more The mechanical characteristics of PEEK-based layered composites with unidirectional carbon fibers fabricated under various compression molding conditions have been investigated. It has been shown that it is possible to increase the modulus of elasticity in transverse bending (up to 60 GPa) and bending at maximum load (up to 770 MPa) by changing the molding pressure (using pre-pressing up to 6.5 MPa at intervals). Composites made at a constant pressure of 8 MPa (170 kJ/m 2) have the maximum impact toughness.
Polymers
Laminated composites based on polyetheretherketone (PEEK) and polyimide (PI) matrices were fabric... more Laminated composites based on polyetheretherketone (PEEK) and polyimide (PI) matrices were fabricated by hot compression. Reinforcing materials (unidirectional carbon-fiber (CF) tapes or carbon fabric) and their layout patterns were varied. Stress–strain diagrams after three-point flexural tests were analyzed, and both lateral faces of the fractured specimens and fractured surfaces (obtained by optical and scanning electron microscopy, respectively) were studied. It was shown that the laminated composites possessed the maximum mechanical properties (flexural elastic modulus and strength) in the case of the unidirectional CF (0°/0°) layout. These composites were also not subjected to catastrophic failure during the tests. The PEEK-based composites showed twice the flexural strength of the PI-based ones (0.4 and 0.2 GPa, respectively), while the flexural modulus was four times higher (60 and 15 GPa, correspondently). The reason was associated with different melt flowability of the use...
AIP Conference Proceedings, 2017
The paper shows possibility to obtain the silica nanoparticles by method realized using experimen... more The paper shows possibility to obtain the silica nanoparticles by method realized using experimental plasma system. The advantages of the installation include its design and absence of necessity chlorine-containing raw materials usage. Studies on the use of different silicate raw material such as, for example, granite (silica content-62.5%), milled glass (silica content-72.5%) and silica sand (silica content-98.5%) were conducted, but only results for silica sand sublimation product are presented in frames of this paper. According to the research the technological features of silica nanoparticles synthesis were identified. X-ray diffraction, transmission electron microscopy and energy-dispersive X-ray spectroscopy were used to characterize the synthesized product. The obtained silica nanoparticles are agglomerated, have spherical shape and primary diameters between 10-30 nm.
Materials
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
European Journal of Wood and Wood Products, 2017
Uploads
Papers by Pavel Kosmachev